sounds like a good strategy, at every job I've worked the first question following a statement of "We need more people" was "Does anybody know somebody who would fit in here ?"
Every time I say "I know the perfect person", my bosses say, "No, we need to 'put the feelers out' and compare. There's no way to know if your guy is perfect without interviewing to see who's out there."
It's silly. They need to feel useful. This reminds me of some previous employers who always breathed down my neck to lay off our current developers and find newer faster developers.
Sometimes you should go for what you have, especially if its highly competent, is vouched for by a valued employee and meets your requirements.
Psychologically difficult (is their a term here?) for singular decisions to be made outside of chaff to discard. Not just in hiring, but, particularly in hiring :)